FINE-STRUCTURE LINE CONTRIBUTION TO IRAS BANDS IN THE ROSETTE NEBULA

The possibility of significant line emission contributing to the 12, 2 5, 60, and 100 mu m infrared emission is explored for the Rosette H Ir region. We find that the [O III] fine-structure lines in the far-infr ared contribute significantly (25%-40%) at both 60 and 100 mu m. All o f the 12 mu m emission is consistent with emission from [S IV] and oth er lines. The [O IV] line can explain the 25 mu m emission near the ce ntral cavity but is unable to explain the strength of the 25 mu m emis sion at more distant lines of sight. Based on the strength of the 25 m u m emission and the high 60/100 ratio, we conclude that a hot dust co mponent within the H II region is necessary and that the best candidat e for this component is ''astronomical'' iron.